Gazprom and Croatian pipeline operator Plinacro are in talks about routing the proposed South Stream pipeline through Croatia rather than Hungary, a Plinacro spokeswoman said on Tuesday.
South Stream, a Russian-backed pipeline project to ship gas from the Caspian region, is expected to cost more than 15 billion euros ($18.51 billion) and export 63 billion cubic meters of gas to southern Europe from 2015.
Croatia and Russia signed an agreement on the South Stream project in 2010, but details were never finalized nor confirmed by either country.
"The fact is that we are having intense talks but the final decision rests with Gazprom," the spokeswoman said.
"We can't say when they will decide, but it could be within a week, a month, or by the end of this year," she added in a telephone interview.
A final investment decision on South Stream, a rival to an EU-backed pipeline project called Nabucco, is expected in November, with construction to start in December.
Other partners in the project include Eni of Italy, France's EDF and Germany's Wintershall.
Russia, which has launched the first line of the 55 billion cubic meter per year Nord Stream pipeline across the Baltic Sea to Germany, continues to push export routes for its conventional gas that bypass transit nations such as Ukraine.